In some scenarios, it may be economically more effective to repair metal components that have suffered cracks and damages, rather than replace them completely. One such repair technique is referred to as narrow groove welding or narrow gap welding in the art. In such a type of welding, the welding operation is typically performed in deep and recessed portions of a work piece. Narrow groove welding may also be beneficial when joining work pieces with thick walls. Normally, narrow groove welding is carried out by an arc welding process. In a conventional arc welding process, a continuous length of welding wire is fed into an arc welding torch. The welding torch passes the welding wire and a contact tip located at one end of the welding torch guides the welding wire to the weld joint. The welding wire acts as a consumable electrode and is fused into an electric arc. The electric arc is created between the welding wire and the base material and melts the metals at the weld joint.
There have been attempts to make narrow groove welds in the past. However, almost all such attempts are subjected to severe challenges. One such challenge is shorting of the welding wire when it comes in contact with the sidewall of the narrow groove. To tackle this problem, the welding wire has to be fed extremely straight into the contact tip so that the welding wire does not touch the sidewalls. This is difficult to achieve in practice, especially, with fine welding wires. Another challenge is that the length of the welding wire (commonly referred to as stick out) can be rather long, e.g., exceed three inches, causing the welding wire to bend. A welding wire that is bent can be very cumbersome and difficult to control during a welding operation. Furthermore, a long stick out increases the tendency for spurious arcing to occur between the welding wire being fed down into the narrow groove and the side walls of the narrow groove.
To make matters worse, current embodiments of the contact tip are traditionally short in length, and are made of a good electrical conductor, typically copper. This creates a two-fold problem when welding in deep and narrow recessed environments. The first problem is that the inadequate length of the contact tip does not allow the contact tip to reach into narrow and recessed portion of a weld joint of a work piece. This problem becomes much more severe in scenarios wherein the weld joint is narrower than the contact tip. The second problem is that, because the contact tip is typically constructed from a material that is a good conductor of electricity, any contact with the surrounding wall of the recessed portion creates a short in the system. For these aforementioned reasons there exists a need to create an assembly that allows for welding in deep and narrow recessed gaps within a work piece.